Air France employees protect themselves from tear gas as they demonstrate amid a strike over pay, on the highway leading to Roissy Charles de Gaulle airport, in Roissy, north of Paris, Thursday, Feb.22, 2018. Air France said that half of its long-haul flights departing from Paris will not operate Thursday and encouraged customers with a Thursday flight reservation to change their ticket "at no extra cost."(AP Photo/Thibault Camus)

Air France employees demonstrate outside the French airline headquarters in Roissy, north of Paris, Thursday, Feb.22, 2018. Air France says that half of its long-haul flights departing from Paris will not operate for 24 hours during a strike over pay. (AP Photo/Thibault Camus)

A passenger information board displays some disruptions at Roissy Charles de Gaulle Airport, in Roissy, north of Paris, Thursday, Feb.22, 2018. Hundreds of angry Air France staff are demonstrating at the French airlines' headquarters in northern Paris amid a strike over pay that has grounded flights. Air France said that half of its long-haul flights departing from Paris will not operate Thursday and encouraged customers with a Thursday flight reservation to change their ticket "at no extra cost." (AP Photo/Thibault Camus)

Air France employees demonstrate outside the French airline headquarters in Roissy, north of Paris, Thursday, Feb.22, 2018. Air France says that half of its long-haul flights departing from Paris will not operate for 24 hours during a strike over pay. (AP Photo/Thibault Camus)

Air France registration desks are deserted at the Roissy Charles de Gaulle airport, in Roissy, north of Paris, Thursday, Feb.22, 2018. Hundreds of angry Air France staff are demonstrating at the French airlines' headquarters in northern Paris amid a strike over pay that has grounded flights. Air France said that half of its long-haul flights departing from Paris will not operate Thursday and encouraged customers with a Thursday flight reservation to change their ticket "at no extra cost." (AP Photo/Thibault Camus)

Air France employees demonstrate outside the French airline headquarters in Roissy, north of Paris, Thursday, Feb.22, 2018. Air France says that half of its long-haul flights departing from Paris will not operate for 24 hours during a strike over pay. (AP Photo/Thibault Camus)

Air France employees demonstrate outside the French airline headquarters in Roissy, north of Paris, Thursday, Feb.22, 2018. Air France says that half of its long-haul flights departing from Paris will not operate for 24 hours during a strike over pay. (AP Photo/Thibault Camus)

Air France said that half of its long-haul flights departing from Paris will not operate Thursday. A quarter of medium-haul flights are cancelled as well as 15 percent of its short-haul flights.

In a statement, Air France said it would be operating 75 percent of its total flights and would be "making every effort to minimize the inconvenience."

But it acknowledged that almost one third of its staff would be participating in the day's action.

Customers with a Thursday flight reservation have been encouraged to change their ticket "at no extra cost."

"Our goal is not at all to generate discomfort but unfortunately, today, it's impossible to even begin to engage in a dialogue with top management and our meetings are totally fruitless," said Eric Faliu, spokesman for the Cabin Crew union.

Thousands of passengers saw their travels plans disrupted, with many left waiting at Charles de Gaulle airport.

French national Yannick Dacosta-Neto, who was heading on vacation, had to take extra time off work to leave earlier after his flight was canceled.

An engaged pilot from Panama, Frias Bock, said he had been "greatly affected" as his wedding plans will be affected by the cancellation of his flight from Paris.